With the continuous development of Internet Protocol (IP) technologies, operators are requiring higher reliable IP networks, and as a highly reliable solution, Non-Stop Route (NSR) technique has emerged. NSR is a technique that is used in a scenario where the control plane of an active board of a router fails and a control plane of a standby board of the router exists, the control plane of a peer is unaware of the failure. The NSR technique is mainly used to enable non-stop routing when routers with standby redundancy are reset upon switchover. That is, the NSR technique enables non-stop forwarding when services are switched on multiple neighboring routers simultaneously.
Group based packetization defined in the Border Gateway Protocol (BGP) is a solution where peers with the same outbound policy are assigned into one packet group, and routes meeting the policy are packetized into packets and the packets are transmitted for multiple times, which greatly increases the efficiency of packet transmission. After BGP group based packetization is implemented, how to combine NSR with group based packetization after an active-standby switchover becomes a new challenge.
In the prior art, after the active board performs switchover, the standby board packetizes local routes into packets and retransmits the packets to all peers. That is, after an active-standby switchover, the standby board directly publishes the packets to the peers again.
During the implementation of the foregoing solution, the inventor discovers that the prior art has at least the following disadvantages: the solution cannot resume transmission from a breakpoint. That is, if an active-standby switchover occurs during the transmission of a packet group, a packet in the transmit buffer is not completely transmitted to some peers. Therefore, for those peers, after an active-standby switchover, the standby board does not resume transmission from their respective breakpoints. Instead, the standby board packetizes all the routes into packets and transmits the packets again. Thus, erroneous packet is produced and large quantities of system and network resources are consumed after the switchover. In addition, the standby board responds slowly to a change of topology.